/*
 * Copyright (c) 2004-2022, University of Oslo
 * All rights reserved.
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 * Redistribution and use in source and binary forms, with or without
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 * 1. Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
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 * 2. Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * 3. Neither the name of the copyright holder nor the names of its contributors 
 * may be used to endorse or promote products derived from this software without
 * specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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package org.hisp.dhis.expression.dataitem;

import static java.lang.String.format;
import static org.hisp.dhis.common.ValueType.NUMBER;
import static org.hisp.dhis.expression.ParseType.INDICATOR_EXPRESSION;
import static org.hisp.dhis.parser.expression.ParserUtils.DOUBLE_VALUE_IF_NULL;

import org.hisp.dhis.antlr.ParserExceptionWithoutContext;
import org.hisp.dhis.common.DimensionalItemId;
import org.hisp.dhis.common.DimensionalItemObject;
import org.hisp.dhis.common.ValueType;
import org.hisp.dhis.common.ValueTypedDimensionalItemObject;
import org.hisp.dhis.parser.expression.CommonExpressionVisitor;
import org.hisp.dhis.parser.expression.ExpressionItem;
import org.hisp.dhis.parser.expression.antlr.ExpressionParser.ExprContext;
import org.hisp.dhis.system.util.ValidationUtils;

/**
 * Parsed dimensional item as handled by the expression service.
 *
 * @author Jim Grace
 */
public abstract class DimensionalItem implements ExpressionItem {
  @Override
  public Object getDescription(ExprContext ctx, CommonExpressionVisitor visitor) {
    DimensionalItemId itemId = getDimensionalItemId(ctx, visitor);

    DimensionalItemObject item = visitor.getDimensionService().getDataDimensionalItemObject(itemId);

    if (item == null) {
      throw new ParserExceptionWithoutContext(
          format("Cannot find %s for %s", itemId.getDimensionItemType().name(), itemId));
    }

    visitor.getItemDescriptions().put(ctx.getText(), item.getDisplayName());

    return ValidationUtils.getNullReplacementValue(getItemValueType(item, visitor));
  }

  @Override
  public final Object getExpressionInfo(ExprContext ctx, CommonExpressionVisitor visitor) {
    visitor.getInfo().getItemIds().add(getDimensionalItemId(ctx, visitor));

    return DOUBLE_VALUE_IF_NULL;
  }

  @Override
  public final Object evaluate(ExprContext ctx, CommonExpressionVisitor visitor) {
    DimensionalItemId itemId = getDimensionalItemId(ctx, visitor);

    DimensionalItemObject item = visitor.getParams().getItemMap().get(itemId);

    Object value = (item != null) ? visitor.getParams().getValueMap().get(item) : null;

    return visitor.getState().handleNulls(value, getItemValueType(item, visitor));
  }

  /**
   * Constructs the DimensionalItemId object for this item.
   *
   * @param ctx the parser item context
   * @param visitor the tree visitor
   * @return the DimensionalItemId object for this item
   */
  public abstract DimensionalItemId getDimensionalItemId(
      ExprContext ctx, CommonExpressionVisitor visitor);

  // -------------------------------------------------------------------------
  // Supportive methods
  // -------------------------------------------------------------------------

  /**
   * Returns the value type of this item.
   *
   * <p>If within an indicator and not a subexpression, always returns number. If in an indicator
   * subexpression or anywhere else (such as validation rule or predictor), returns the item's data
   * type if it has one (defaulting to number).
   */
  private ValueType getItemValueType(DimensionalItemObject item, CommonExpressionVisitor visitor) {
    if (item instanceof ValueTypedDimensionalItemObject
        && (visitor.getParams().getParseType() != INDICATOR_EXPRESSION
            || visitor.getState().isInSubexpression())) {
      return ((ValueTypedDimensionalItemObject) item).getValueType();
    }

    return NUMBER;
  }
}
